Ответ:
6÷5 = x÷75 a÷1 7/50 = 5/57 ÷ 1/2
5x = 6×75 a/1 7/50 = 5/57/1/2
5x = 450 a/57/50 = 10/57
x = 90 50a/57 = 10/57
50a = 10
a= 1/5
x/0,8 = 15/4 5-y/4 = 3/7
x/4/5 = 15/4 7(5-y) = 12
5x/4 = 15/4 35-7y = 12
5x = 15 -7y = -23
x = 3 y = 23/7
Пошаговое объяснение: